Table 1.

Means (± standard errors) of jaw length and muscle architectural variables for Cebus apella, C. albifrons, and C. capuchinus and Mann-Whitney U-test results comparing C. apella to the two untufted capuchins.

	Cebus apella	Cebus albifrons	Cebus capuchinus	C. apella vs. untufted capuchinsa,b
Masseter Ls (µ)c,d	2.35 ±0.04	2.43 ±0.10	2.50 ±0.07	NS
Temporalis Ls (µ)c,d	2.46 ±0.07	2.40 ±0.06	2.44 ±0.05	NS
Jaw length (mm)	61.04 ±1.23	55.98 ±2.10	57.97 ±1.07	C. apella > 0.0491*
Masseter length (mm)	37.50 ±2.52	28.60 ±2.92	34.93 ±2.43	C. apella > 0.0938
Temporalis length (mm)	64.13 ±2.61	49.50 ±2.16	57.57 ±1.91	C. apella > 0.0128
Superficial Masseter Muscle
Mass (g)	5.94 ±0.83	3.41 ±0.97	2.86 ±0.35	C. apella > 0.0253*
NLf (mm)d	11.12 ±1.07	8.58 ±0.97	10.18 ±2.73	NS
PCSA (cm2)d	4.87 ±0.60	3.31 ±0.86	2.84 ±0.57	C. apella > 0.0510
Deep Masseter Muscle
Mass (g)	1.04 ±0.18	0.53 ±0.32	0.59 ±0.10	C. apella > 0.0345*
NLf (mm)d	7.33 ±0.91	5.09 ±0.26	6.68 ±1.90	NS
PCSA (cm2)d	1.29 ±0.18	1.07 ±0.49	0.71 ±0.18	NS
Whole Masseter Muscle
Mass (g)	6.97 ±0.95	3.83 ±1.09	3.44 ±0.44	C. apella > 0.0109
NLf (mm)d	9.31 ±0.79	7.48 ±0.51	9.82 ±2.85	NS
PCSA (cm2)d	6.66 ±0.70	4.56 ±1.39	3.58 ±0.75	C. apella > 0.0510
Temporalis Muscle
Mass (g)	13.66 ±2.35	6.92 ±2.82	5.98 ±0.58	C. apella > 0.0164
NLf (mm)d	14.02 ±1.34	12.48 ±1.39	14.37 ±3.19	NS
PCSA (cm2)d	8.84 ±1.06	4.88 ±1.57	4.20 ±0.72	C. apella > 0.0075

^aResults based on two-tailed Mann-Whitney U-tests.

^bBoldfaced p-values identify significant differences following the sequential Bonferroni adjustment.

Starred (*) p-values identify significant differences prior to the sequential Bonferroni adjustment. Unstarred p-values identify differences where 0.05 < p < 0.10. NS = non-significant.

^cAverage sarcomere lengths exclude the C. apella specimen fixed at a wide jaw gape.

^dLs, sarcomere length; NLf, normalized fiber length; PCSA (cm²), physiologic cross-sectional area.